RADIO REVIVES '70S TUNES; PILES ON DESIRABLE LISTENERS

A 1970s music play-list including the likes of Donna Summer, Elton John and BTO is climbing the charts. Again.

Only this time around, it's not Billboard's top 100. Instead, '70s music is catching on with broad casters as they grapple over what music format to offer on their second FM and AM stations in markets where they have duopolies.

In 1992, the Federal Communications Commission raised the number of stations a broadcaster could own in a single market from one FM and one AM to two of each. With the new duopoly ruling in place, Shamrock Broadcasting last year picked up country station KSAN-FM and oldies KABL-AM. It already owned country station KNEW-AM and KABL-FM.

Last month, Shamrock switched KABL-FM in San Francisco to all '70s pop and rock music after a year of adult contemporary hits from the '80s and '90s.

"Niche formats have become a viable option, in crowded markets with a duopoly," said Eddie Esserman, VP-general manager of Shamrock's San Francisco properties.

Programmers believe '70s rock won't cannibalize their other formats, but rather will bring in new listeners.

"Obviously, you look for formats that are compatible with existing formats," said Robert Neil, exec VP-radio at Cox Enterprises.

Cox had broadcast adult contemporary music and classic rock 'n' roll on WCKG-FM in Chicago and WWRM-FM in Tampa, Fla.

In January, Cox introduced the '70s music format on its newly acquired WYSY-FM in Chicago and last year brought the format to WCOS-FM in Tampa. WCOS previously broadcast album-oriented rock; WYSY programmed a split format, airing adult contemporary during the day and heavy metal at night. Cox supports its stations with local TV, via Film House, Nashville, Tenn. Both Shamrock and Cox declined to discuss budgets, but Cox is believed to be spending nearly $1 million on the combined markets.

While the programming change at WCOS is too recent for year-to-year comparison, Arbitron Co. rated the station 14th in its market with a 1.3 share in summer '93. Arbitron's quarterly survey, Arbitrends, ranked WCOS No. 2 in its market with an 8.9 share for the last quarter of 1993.

Mr. Neil explained, however, there is no corporate philosophy to put '70s music on all Cox's second FM or AM stations. The Atlanta-based media company owns 15 radio stations in the U.S., as well as TV stations and The Atlanta Journal and The Atlanta Constitution.

But station owners increasingly are adapting formats to attract an audience between ages 25 and 49.

In the mid-1970s and '80s, oldies stations proliferated, airing music from the '50s and '60s aimed at 25-to-49-year-olds. But as that group aged, more stations have begun playing music popular with baby boomers.

"We've been waiting to see if someone was going to home in on that," Mr. Taylor said. "It was an inevitable thing."